1. Field of the Invention
This invention relates to a backlight device and a liquid crystal display equipment with the backlight device, in particular to a backlight device which does not have influence of electromagnetic interference upon a displaying operation of a liquid crystal display panel, and a liquid crystal crystal display equipment with the backlight device.
2. Description of the Prior Art
In recent years, liquid crystal display panels have been used as image displaying planes of personal computers, word processors, various meters, television sets, etc. A backlight device has been used as an auxiliary device to finely display characters or images in the display panel by irradiating a light from the back of the display panel.
The conventional backlight device has a plurality of fluorescent lamps as a light source thereof and a light diffusion plate for making a uniform illumination plane by diffusing the light irradiated from the fluorescent lamps and transmitting therethrough. Each of the fluorescent lamps is so designed as to be irradiated by an electric discharge. Therefore, in order to ensure the discharge and the lighting of the fluorescent lamps, alternating voltage of 1000V is applied to the lamps from an electric power source through an inverter circuit substrate.
The fluorescent lamps are so made as to switch on by applying thereto such a high AC voltage as described above. Accordingly, an electromagnetic field having a high intensity is generated around each of the fluorescent lamps lighted. As a result, in the conventional backlight device, there has been such a troublesome problem that the high intensity electromagnetic field causes interference with operating signals for the liquid crystal display panel, so that a striped pattern is generated in the display panel which makes it difficult to see an image or characters displayed in the liquid crystal display panel.